The inventor studied about a technique of rapidly recognizing an absolute position of a moving body such as a stacker crane, a rail guided vehicle, or an overhead traveling vehicle with a high degree of accuracy on the ground side. If this is achieved, it is possible to easily implement running control and stop control of the moving body, and avoid collision and jamming. For this purpose, it is necessary to detect the position of the moving body along a moving route continuously without any interruption, or almost continuously. Further, since each linear sensor outputs a relative coordinate relative to the origin of the linear sensor, the relative coordinate needs to be converted into an absolute position. Patent Publication 1 (Japanese Patent Application No. 2006-218694) discloses a technique of detecting a position of a moving body using linear sensors.